Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for HD 189733: 10-19 (100), 10-20 (100), 10-21 (100), 10-22 (100), 10-23 (100) — by astronomy; check the weather when the night is within four days.

2027-10-11astronomy score per night — click a bar for that night2027-11-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-11 Mon	36	—	unknown	20:20–01:20 (marginal, 5.0 h)	71.1° 20:05	9.63	87%	47.0°
2027-10-12 Tue	34	—	unknown	20:20–01:10 (marginal, 4.83 h)	71.1° 20:00	9.68	93%	52.7°
2027-10-13 Wed	37	—	unknown	20:20–01:00 (marginal, 4.67 h)	71.1° 19:55	9.72	97%	60.1°
2027-10-14 Thu	43	—	unknown	20:15–20:55 (good, 0.67 h)	71.1° 19:50	9.77	99%	68.5°
2027-10-15 Fri	51	—	unknown	20:15–22:10 (good, 1.92 h)	71.1° 19:45	9.81	100%	77.6°
2027-10-16 Sat	63	—	unknown	20:15–23:05 (good, 2.83 h)	71.1° 19:45	9.85	98%	87.3°
2027-10-17 Sun	76	—	unknown	20:10–00:05 (good, 3.92 h)	71.1° 19:40	9.9	94%	97.1°
2027-10-18 Mon	89	—	unknown	20:10–00:25 (good, 4.25 h)	71.1° 19:35	9.94	88%	106.9°
2027-10-19 Tue	100	—	unknown	20:10–00:25 (good, 4.25 h)	71.1° 19:30	9.98	80%	116.4°
2027-10-20 Wed	100	—	unknown	20:10–00:25 (good, 4.25 h)	71.1° 19:25	10.02	70%	125.1°
2027-10-21 Thu	100	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:25	10.07	59%	132.2°
2027-10-22 Fri	100	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:20	10.11	48%	136.8°
2027-10-23 Sat	100	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:15	10.15	36%	138.1°
2027-10-24 Sun	100	—	unknown	20:00–00:20 (good, 4.33 h)	71.1° 19:10	10.19	26%	135.4°
2027-10-25 Mon	100	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:10	10.23	16%	129.6°
2027-10-26 Tue	100	—	unknown	20:00–00:10 (good, 4.17 h)	71.1° 19:05	10.27	9%	121.5°
2027-10-27 Wed	100	—	unknown	20:00–00:05 (good, 4.08 h)	71.1° 19:00	10.31	4%	112.1°
2027-10-28 Thu	100	—	unknown	19:55–00:00 (good, 4.08 h)	71.1° 18:55	10.34	1%	102.1°
2027-10-29 Fri	100	—	unknown	19:55–00:00 (good, 4.08 h)	71.1° 18:50	10.38	0%	91.9°
2027-10-30 Sat	100	—	unknown	19:55–23:55 (good, 4.0 h)	71.1° 18:50	10.42	2%	81.9°
2027-10-31 Sun	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:45	10.46	6%	72.3°
2027-11-01 Mon	100	—	unknown	18:55–22:45 (good, 3.83 h)	71.1° 17:40	10.49	12%	63.4°
2027-11-02 Tue	96	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:35	10.53	20%	55.5°
2027-11-03 Wed	84	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:30	10.57	28%	49.0°
2027-11-04 Thu	71	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:30	10.6	37%	44.3°
2027-11-05 Fri	58	—	unknown	18:50–22:15 (good, 3.42 h)	71.1° 17:25	10.64	46%	41.9°
2027-11-06 Sat	48	—	unknown	18:45–21:50 (good, 3.08 h)	71.1° 17:20	10.67	56%	42.3°
2027-11-07 Sun	40	—	unknown	18:45–20:05 (good, 1.33 h)	71.1° 17:15	10.7	65%	45.2°
2027-11-08 Mon	34	—	unknown	18:45–19:05 (good, 0.33 h)	71.1° 17:15	10.74	74%	50.4°
2027-11-09 Tue	31	—	unknown	18:45–22:25 (marginal, 3.67 h)	71.1° 17:10	10.77	82%	57.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-11&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.